Description: The new SCAF-1 filter from Ham Supply/Idiom Press makes your radio
listener friendly,
whether you are an SSB or CW operator. Using a modern but little
known technology
called SCAF filtering, the SCAF-1 is an active audio low pass filter
offering user control of
the filter cut-off frequency, yielding a stunning 96dB per octave roll-off
of signals above
the cut off frequency, and no white noise. It is the perfect partner for
your crystal or
mechanical filters. And, unlike most audio filters, there is absolutely NO
ringing.

Purchased as an assembled unit several years ago. I am currently using this on an old TT Argonaut 509. Completely eliminates the high frequency hiss and white noise, making copy much less fatiguing. Signals which were buried become copyable. For older rigs that lack the newer features this is a very useful accessory and I highly recommend it. It's small enough it can sit on top of my FT-817 easily. Simple to use.

Back when I ordered mine I waited a long time for delivery, then sent a polite email inquiring about my order. I received a reply that basically said, "we are behind, sorry you had to wait so we will only charge you the kit price". I'm still impressed by that.

I built & have used the SCAF-1 since 2002. It is an excellent alternative to IF CW filters optioned in low-end HF transceivers. I use mine exclusively with an IC-718 and find I can "weed out" most any adjacent signal. If compared to a 500 Hz IF CW filter I recently installed in my IC-703; I'd say the SCAF-1 is an excellent buy. It's fun to build and performs as stated.

2) Components are in normal grade but much better than those China brand kits.

3) Cosmetic is very good. Looks smart and much better than those MFJ products.

4) It's really helpful to reduce the noise in SSB & CW mode. The roll off is very sharp. I can't found out the difference between using the most narrow bandwidth of this filter to listen the morse code in CW with 600Hz IF filter or in SSB mode with 2.4kHz IF filter.

5) When switching on the power, a very loud "Po" noise will be heard but it is acceptable on this kind of low cost product.

General speaking, if you want to pay higher cost to buy DSP filter like Timewave, I suggest you to save the money and try this little box first.

I have built only a few kits and am by no means a true ham with the “knack”. To me building a kit is like putting a puzzle together with at the end a piece of equipment that I can actually use.

The kit arrived quickly, all parts were counted for. A professional made printed circuit board a case are almost a guarantee to end with professional looking device. The manual is well written but it certainly could use a few images to shed a light on some parts of the construction. In particular the wiring is very hard to follow. Further I made a mistake by soldering the diodes in exactly the wrong directly as the should have been. This leads to my main complaint of this kit. There is no support. During the build I wasn’t clear about the diodes and despite reading the instructions carefully I was not 100% sure and decided to pause the project and call Idiom Press. I left a voicemail and have yet to receive a call back :-(

After I connected all the wires and turned the filter on I could not hear any difference in the audio. I started to look for clues and verified all the connections. In the hope that an expert might spot my mistake(s) easily I send a number off pictures to Idiom Press in the hope to receive some support. Until today the email has remained unanswered :-(

I ended up removing the circuit board from the wiring and started the diagnostics with a minimal system set-up. It turned out that the fault was on the circuit board and not the wiring. Since I had trouble understanding how the diodes were supposed to be mounted I painfully extracted the parts and put them back in the reversed direction. Voila it works

This filter does a great job cleaning up CW signals. Together with the 250 kHz narrow CW filter I can easily decode signals that where otherwise very hard to detect. On SSB however the effect is less noticeable.

This is one of these pieces of kit that, once you've got it, you can't remember how got by without it! Firstly, the kit is very easy to put together, with very well written, clear, step by step instructions. If you are careful and take your time you will end up with a very neat looking addition to the shack which works first time, as mine did. A user manual is really not needed as there are only 2 controls on the front of the unit, and one of these is the on/off switch! Basically, regardless of mode, you just turn the "width" controller till you get a pleasant sounding result, whether that be SSB or CW, which is my favourite mode, and in this mode, the filter excells. In my humble opinion this filter is as good as any I have tried, and I have tried a few, including a DSP filter by MFJ, an audio filter by Diawa and a couple of Datong FL-3's, remember it is not a crystal filter, but it does not claim to be, it does a very good job of filtering out unwanted signals. I would rate this as a must have for CW ops. All in all, a great sounding, useful, and, most importantly, a nice looking bit of kit that gives you the satisfaction of knowing you built it with your own fair hand.

I've been aware of the SCAF-1 for some time but doubted the effectiveness of an audio filter to improve CW selectivity. During a recent kit building binge, I decided to try one for use at my vintage station with a Hammarlund HQ-160 receiver. What a difference! The HQ-160 isn't noted as a selectivity champ but does have a very effective slot (notch) filter and a Q-multiplier which can provide decent selectivity when properly adjusted. Still, it requires lots of knob twisting and nudging to attain usable CW selectivity. With the SCAF-1 switched in the difference is profound. The passband is quickly and easily narrowed with one knob. Signals really stand out and copy is considerably improved. Very strong, very close signals may still cause desensitization - after all, this is only an audio filter, but I've found the HQ-160's slot filter placed right on top of the offending signal takes care of it. Using the slot filter without the SCAF-1 still allows the offending signal to be heard; with the SCAF-1 and notch, the offending signal is gone. Most often, the SCAF-1 alone is all that's required to provide the necessary selectivity for single-signal reception.

SSB readability is also greatly improved at the widest setting of the passband knob on the SCAF-1. The HQ-160 passband is so wide that just switching in the SCAF-1 makes a substantial difference in readability.

I'm thrilled with this product. I love to operate vintage equipment, especially on CW, and the SCAF-1 makes all the difference. Best of all, I can use it to clean up the selectivity of just about any old boatanchor receiver I may want to play with. In combination with the HQ-160 with its slot filter, the result is a very competent CW receiver which was only average before the SCAF-1 was installed. The SCAF-1 removes much of the suffering of trying to copy CW with less capable boatanchors such as an NC-88, SX-99, etc.

My SCAF-1 came as a kit which required about 6 hours to assemble including inventory & sorting/organizing the parts. Assembly instructions are well written. The kit uses several discrete wires connecting the DPDT toggle switch, passband pot and the audio input & output jacks which slows down the building process a bit. Otherwise, assembly is straightforward and shouldn't pose any difficulty. This would be a good kit for a first-time builder. The kit includes a very high quality two-piece cabinet which is pre-drilled and nicely labeled on the front panel. The rear panel has no labels oddly enough. Audio input from the radio is an RCA jack. There are 1/4" and 1/8" output jacks and the builder has a choice of which is used for a speaker or headphones. The output jacks may also be wired as stereo (3 conductor) or mono (2 conductor) plugs. 12VDC power input is provided through a 5.5 x 2.1mm standard coaxial jack. I used a 12V 1A regulated wall-wart from Jameco which uses a built-in 3-terminal regulator IC, ample filtering and provides a stable 12.6VDC source. Otherwise 12-13.8VDC station power may be used. The unit is very small and easily integrates into an existing setup.

If you're a CW op and love to play with vintage/antique gear, I hope you try the SCAF-1. I can see how this product may not make a profound difference when used with modern equipment with already good selectivity but with vintage equipment, the result is astounding.

I wasn't as impressed as everyone else seems to be with my SCAF-1. Yes, it works okay, but doesn't go very narrow for CW work. For SSB, if you adjust it narrow enough to make a difference, it makes the voices muffled (which I hate listening to).

Maybe I was spoiled with the SCAF on the SGC SG-2020 HF transceiver which would narrow right down to 100Hz for single signal CW copy (fantastic), but the SCAF-1 doesn't go that narrow.

After a month or two of using it, I sold it and bought a 250Hz crystal CW filter instead (which did a far better job on CW).

The samples on the Idiom Press web site sound great, but I didn't get results as good as those.

There are a goodly number of Audio-type filters available, but after considering, and then discarding some of the candidates I finally, and happily settled on the Idiom SCAF-1. It's a perfect addition to my Ten Tec Argonaut V; it does exactly what is advertised and delivers the kind of listening comfort, that I feel, is welcome in today's DSP environment. As well, the EHAM REVIEWS were instrumental in acting on my choice, and if I may suggest---anyone with a DSP rig might want to consider this option for a more relaxed and pleasurable listening experience. I might add that this was my third dealings with Idiom Press---great products, great service, and a great company.
73---Ernie
VE3GNU

Hi. A great deal of the time while at my PC, I have my FRG-7 running. I have all the Kiwa mods and think very highly of this receiver.

A LOT of the time, I listen to the 'stuff' on 14.275. It seems like everyone tunes up there or QRMs the other stations just for fun.

Today, there were a lot of carriers around that trequency. I found that the SCAF-1 removes those hetrodynes almost as good as the 'Notch' in my 756PRO. The Automatic Notch in the PRO never ceases to amaze me!

I helped Idiom Press with the Manual several years ago and I have my NR knob wired to increase the NR as the knob is turned CW.

It is also excellent for removing the bleed-over from nearby stations.

My IC703 has a stock SSB filter, and for CW sometimes the CW-reverse feature and IF-shift don't provide enough selectivity. The SCAF-1 is a useful and economical low-pass active audio filter. The kit is easy to assemble and does definitely provide clean low-pass filtering, you can see it assembled and hear how it works at http://www.youtube.com/user/NG9D?feature=mhum The recording is from this weekends CW contest. Kit ordered last Wed, delivered Fri and assembled and tested over the weekend. 73 de NG9D